b'WHEAT MIDGEWHEAT MIDGE: PROTECTING AGAINST ANOTHER OUTBREAKWITH THE MANY challenges 2020 brought the world, its noFor more than a decade, these varieties have been the first surprise orange blossom wheat midge picked last year to showline of defence against the pest. Midge tolerant wheat growers up in full force in fields across the Prairies. report significant yield and grade benefitsapproximately We actually had the biggest outbreak of wheat midge that Ive$36 per acre. There are now more than 35 varieties available in seen in my short career, says Tyler Wist, research scientist ofseven different wheat classes. field crop entomology with Agriculture and Agri-Food CanadaMidge tolerance in all varieties originates from a single gene in Saskatoon, Sask. Results of the annual wheat midge surveycalled Sm1, which increases the level of phenolic acids in the that comes out in January 2021 will include the data that wewheat kernel and discourages feeding by the pest. As a result, need to show a population increase, but the spring rains werethe midge starve and die.perfect for midge development. Wist says the overall midge population had been decreasing over the past decade in Western Canada, in part, due to dry growing conditions. He explains larvae overwinter in the soil in larval cocoons and require adequate moisture in May and June to bring them to the soil surface. Above-average rainfall last spring in some parts of the Prairies made conditions ideal for the pest to thrive.The Prairie Pest Monitoring Network ran models in mid- We actually had the biggest August to determine potential numbers of overwintering wheatoutbreak of wheat midge that midge larvae. Results predicted higher densities of wheat midge compared to 2019. Alberta was also forecast to have greaterIve seen in my short career.populations than Saskatchewan and Manitoba. Though the Tyler Wistactual impact will be confirmed once survey data is compiled and analyzed during winter 2020, its certain some growers will see the effects of wheat midge this harvest. Impacts on Yield and QualityOrange wheat blossom midge can seriously damage yield and quality of susceptible wheat varieties.All varieties are sold as a blend of midge tolerant and midge In late September, the Canadian Grain Commissionsusceptible wheat, providing an interspersed refuge system confirmed midge was present in the 2020 durum and wheatwhich disrupts the midges ability to produce resistant offspring, crops. In order to determine damage, growers are encouragedpreventing a build-up of a resistant midge population. As Sm1 to look for rupture of the bran on the back or side of kernels, ais the one and only midge tolerant gene, growers must do their white line or mark on the back or side, or a distorted kernel. part to protect the technology. All growers sign a stewardship As Wist explains, wheat midge larvae damage the wheatagreement and commit to maintaining the refuge by limiting the kernels by feeding directly upon them as they are developing.use of farm-saved seed to one generation past certified.Typically, four or more larvae per kernel, which is often the number of eggs laid by a female on one floret, will cause aPlanning for the 2021 Growing Seasoncomplete shrivelling of the kernel and it will blow out the backGiven the right conditions, such as consecutive wet springs, of the combine and be lost as phantom-yield loss, he says.midge populations can build quickly.Less larvae inside a floret, can cause distortion of the kernel,(2020) could be a building year for the midge population splitting of the bran or simply a white line. Too many of thesewith trouble coming (in 2021), says Wist. Well know better kernels in your sample can cause downgrading because midge- once the midge survey is complete.damaged kernels negatively affect the milling performance. In the meantime, as growers plan for the 2021 season, ensuring stewardship protocols are being followed or Midge Tolerant Wheat Varieties purchasing certified midge tolerant wheat are solid steps to Growers who are less inclined to worry about downgrading by theprevent midge outbreaks and to protect future yield and quality.elevator are those who planted midge tolerant wheat in the spring. The Midge Tolerant Wheat Stewardship Committee34seed.ab.ca'